Q441. Refer to the exhibit.
Which statement is true about a VPNv4 prefix that is present in the routing table of vrf one and is advertised from this router?
A. The prefix is advertised only with route target 100:1.
B. The prefix is advertised with route targets 100:1 and 100:2.
C. The prefix is advertised only with route target 100:3.
D. The prefix is not advertised.
E. The prefix is advertised with route targets 100:1, 100:2, and 100:3.
The route target used for prefix advertisements to other routers is defined on the route-target export command, which shows 100:1 in this case for VPNv4 routes.
Q442. Which three benefits does the Cisco Easy Virtual Network provide to an enterprise network?
A. simplified Layer 3 network virtualization
B. improved shared services support
C. enhanced management, troubleshooting, and usability
D. reduced configuration and deployment time for dot1q trunking
E. increased network performance and throughput
F. decreased BGP neighbor configurations
Q443. DRAG DROP
Drag and drop the Cisco IOX XE subpackage on the left to the function it performs on the right.
Q444. Which congestion-avoidance or congestion-management technique can cause global synchronization?
A. Tail drop
B. Random early detection
C. Weighted random early detection
D. Weighted fair queuing
Tail drop treats all traffic equally and does not differentiate between classes of service. Queues fill during periods of congestion. When the output queue is full and tail drop is in effect, packets are dropped until the congestion is eliminated and the queue is no longer full.
Weighted Random Early Detection
WRED avoids the globalization problems that occur when tail drop is used as the congestion avoidance mechanism on the router. Global synchronization occurs as waves of congestion crest only to be followed by troughs during which the transmission link is not fully utilized. Global synchronization of TCP hosts, for example, can occur because packets are dropped all at once. Global synchronization manifests when multiple TCP hosts reduce their transmission rates in response to packet dropping, then increase their transmission rates once again when the congestion is reduced.
Reference: http://www.cisco.com/c/en/us/td/docs/ios/12_2/qos/configuration/guide/fqos_c/qcfconav.ht ml#wp1002048
Q445. Which EEM event detector is triggered by hardware installation or removal?
A. Enhanced-Object-Tracking Event Detector
B. Resource Event Detector
C. OIR Event Detector
D. CLI Event Detector
Q446. Refer to the exhibit.
Route exchange is failing on a PE edge device configured with this VRF-Lite. Which action can you take to correct the problem?
A. Configure the vrf-lite capability under the OSPF address families.
B. Correct the route descriptors.
C. Correct the OSPF router-ids.
D. Configure the control plane with a larger memory allocation to allow the device to appear in the routing table.
Open Shortest Path First version 3 (OSPFv3) operates in nondefault VPN routing and forwarding (VRF) instances for both IPv6 and IPv4 address families and, transports the routes across a Border Gateway Protocol (BGP) or a Multiprotocol Label Switching (MPLS) backbone. On the provider edge (PE) device, customer routes are installed together by OSPFv3 and BGP in a common VRF or address family and each protocol is configured to redistribute the routes of the other. BGP combines the prefixes redistributed into it with a route-distinguisher value defined for the VRF and advertises them to other MPLS-BGP speakers in the same autonomous system using the VPNv4 or VPNv6 address family as appropriate. The OSPFv3 route selection algorithm prefers intra-area routes across the back-door link over inter-area routes through the MPLS backbone. Sham-links are a type of virtual link across the MPLS backbone that connect OSPFv3 instances on different PEs. OSPFv3 instances tunnel protocol packets through the backbone and form adjacencies. Because OSPFv3 considers the sham-link as an intra-area connection, sham-link serves as a valid alternative to an intra-area back-door link. Domain IDs are used to determine whether the routes are internal or external. They describe the administrative domain of the OSPFv3 instance from which the route originates. Every PE has a 48-bit primary domain ID (which may be NULL) and zero or more secondary domain IDs.
How to Configure VRF-Lite/PE-CE
. Configuring a VRF in an IPv6 Address Family for OSPFv3
2. configure terminal
3. vrf definition vrf-name
4. rd route-distinguisher
6. router ospfv3 [process-id]
7. address-family ipv6 [unicast] [vrf vrf-name]
Q447. Which statement about OSPF multiaccess segments is true?
A. The designated router is elected first.
B. The designated and backup designated routers are elected at the same time.
C. The router that sent the first hello message is elected first.
D. The backup designated router is elected first.
According to the RFC, the BDR is actually elected first, followed by the DR. The RFC explains why: “The reason behind the election algorithm’s complexity is the desire for an orderly transition from Backup Designated Router to Designated Router, when the current Designated Router fails. This orderly transition is ensured through the introduction of hysteresis: no new Backup Designated Router can be chosen until the old Backup accepts its new Designated Router responsibilities. The above procedure may elect the same router to be both Designated Router and Backup Designated Router, although that router will never be the calculating router (Router X) itself.”
Reference: http://www.ietf.org/rfc/rfc2328.txt – Page 76
Q448. Refer to the exhibit.
RIPv2 authentication is failing on a device with this configuration. Which two actions can you take to enable it? (Choose two.)
A. Set the RIP authentication mode to text.
B. Set the RIP authentication mode to MD5.
C. Configure the password encryption for the key.
D. Set the password encryption to AES.
See the reference link below for information on configuring RIPv2 authentication, including both test and MD5 modes.
Q449. What are the three HDLC operating modes? (Choose three.)
A. normal response
B. asynchronous balanced
C. synchronous response
D. asynchronous response
E. normal balanced
F. synchronous balanced
Q450. Which packet does a router receive if it receives an OSPF type 4 packet?
A. hello packet
B. database descriptor packet
C. link state update packet
D. link state request packet
E. link state acknowledge packet
To know more about the 400-101, click here.